THE SUN. 57 



of the reversing layer was disputed by numerous 

 astronomers. In 1896 photographs taken during 

 the solar eclipse of that year finally demon- 

 strated the existence of the "flash spectrum" 

 as seen by Young. 



The last of the solar appendages, the corona, 

 can only be seen during total eclipses. The 

 researches of Young and Janssen indicate that 

 it is partly gaseous and partly meteoric in its 

 constitution ; and various photographs, taken at 

 the eclipses since 1870, have demonstrated its 

 variation in shape, which is in harmony with 

 the eleven-year period. Several attempts have 

 been made to observe the corona without an 

 eclipse. In 1882 Huggins made the attempt, 

 but failed, and Hale, with his photographic 

 process, had no better success. More recently, 

 in 1904, a Russian astronomer, Alexis Hansky, 

 observing from the top of Mont Blanc, secured 

 some photographs on which he believes the 

 corona is represented, but so far his obser- 

 vations have not been confirmed by other 

 astronomers. 



The application of the spectroscope to the 

 motions on the solar surface is perhaps one 

 of the most wonderful triumphs in astronomical 

 science. In 1842 Christian Doppler (1803-1853), 

 Professor of Mathematics at Prague, had ex- 



